1. Field of the Invention
The present invention relates to an improved arrangement for a welded pressure (clamping) flange assembly for an electric induction machine having no housing.
2. Description of the Prior Art
FIG. 1 is a simplified plan view, half in section, of a known type 1GH5 rotary induction machine made by Siemens AG, assignee of the present application. The machine includes a yoke lamination stack 1 having wound laminated stator pole bodies 2, a wound rotor lamination stack 8 mounted on a rotor shaft 7, and end bells 5 and 6 supporting the shaft. The end bells are detachably fastened to polygonal flange arrangements 3 and 4 at respective ends of the yoke lamination stack. The polygonal flange arrangements 3 and 4 are essentially square with bevelled corners (i.e., octagonal) and are welded at the corners to flat strips or straps (not shown). The flat straps are parallel to the longitudinal axis and, with the pressure flange, form a frame. The yoke lamination stack 1 is held together under pressure exerted by the end flanges. The flat straps are also welded to the yoke lamination stack. The frame carrying the yoke lamination stack replaces the usual housing for the machine.
Pressure flange arrangement 3 comprises a one piece flange that is positioned on the drive side. Pressure flange arrangement 4 is a welded frame-like assembly with a peripheral surface that has an angular (octagonal) contour (shape). A passage (opening) 4B is positioned on (located in) one side of the assembly. Yoke lamination stack 1, along with the planar side portion of flange 4 containing passage 4B, supports a terminal box 9 detachably fastened on the planar wall portion. Passage 4B contains connecting conductors, not shown in FIG. 1, that connect to terminals, not shown, in terminal box 9.
Pressure flange arrangement 4 comprises a multisection wall that has an angular contour (polygonal shape). The sections of the wall have bevelled ends that are welded together from the inside. The outer periphery of the wall is welded to one piece flat polygonal flange at the end of the wall facing the yoke lamination stack. Mounting pieces rest against and are welded to the inside of the wall portions in the vicinity of the bevelled ends of the wall portions at the outer end of the flange. The pressure flange arrangement on the backside comprises a multiplicity of parts that have an elaborate shape and a corresponding large number of welds. The welds on the outside must be smoothed. The smoothing operation requires considerable rework, especially in the vicinity of the terminal box.